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What is Lynch Syndrome (HNPCC)

Hereditary Nonpolyposis Colon Cancer (HNPCC), sometimes referred to as Lynch syndrome, predisposes people to develop colon cancer, as well as other cancers. HNPCC is caused by a mutation in one of several “mismatch-repair genes.” These mismatch-repair correct "spelling errors" in DNA that happen during the cell division process. When these genes are altered, or mutated, however, mismatches in the DNA remain which will eventually lead to uncontrolled cell growth and tumor formation.

The risk of developing cancer when one has HNPCC is high. There are a number of rare cancers that HNPCC increases the risk of developing, although the main risks are:

  • Colorectal cancers (80%)
  • Endometrial cancer (40-60%)
  • Gastric cancer 15-20%)
  • Ovarian cancer (12%)

HNPCC accounts for about 2-5% of all incidences of colon cancer.

Learn more about Cancer and Genetics.

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